Canals and pores of the cephalic laterosensory system of Characiformes (Ostariophysi): anatomy and its phylogenetic information.

Author(s)

Murilo Nogueira de Lima Pastana

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC)
• Defense date: 2014-11-27

Examining board members

Flávio Alicino Bockmann; George Mendes Taliaferro Mattox; Cristiano Luís Rangel Moreira

• Advisor: Flávio Alicino Bockmann

Abstract

The laterosensory system of fishes is responsible, among other functions, for the perception of water movement and vibration. The functional unit of this system is the neuromast, which can be present on the skin surface or in grooves on it, or also in canals that are distributed along dermic bones, reaching the skin surface by pores. The ossification pattern related to the laterosensory canals is conserved among distinct fish lineages so that this morphological complex may represent a rich source of phylogenetic information. This system has been extensively used in cladistics analysis on several Ostariophysans, such as in Siluriformes and Cypriniformes. However, the laterosensory system of Characiformes, one of the most diverse order of teleost and also a member of the superorder Ostariophysi, has not been described in details yet, and its phylogenetic implications are poorly investigated. The present study aimed on performing an investigation on the laterosensory system components of Characiformes, having as its main goals: 1) a description of the cephalic laterosensory canals and branches for all main lineages of the order; 2) a characterization the canals ending points, i.e. the pores that open on the skin surface; and 3) a interpretation of the main philogenetical implications related to the laterosensory system among Characiformes and Ostariophysi. In order to accomplish these goals, a total of thirty-six Characiformes taxa were analysed, encompassing all families and main subfamilies of this order. Added to that, another thirteen representatives of other Ostariophysans, as well as seven taxa of other Teleostei were included to the comparative analysis as out-group material. As one of the main results of this survey is the acknowledgement that the distribution of the canals os the laterosensory system, as well as the number of branches and pores in association to this complex show little variation between the different lineages of Characiformes, keeping relatively stable among other Ostariophysi. This is interpreted as evidence that morphological traits in relation to this system may be very informative on a phylogenetical context when combined to other sources of characters. Therefore, these results indicate that features of the canals and pores of the laterosensory system may be one more source of anatomical characters, that even not traditionally used, are potentially informative on what regards the the relationship of fishes. (AU)

• FAPESP's process: 12/22685-2 - Canals and pores of the cephalic laterosensory system of Characiformes (Ostariophysi): anatomy and phylogenetic information.
• Grantee: Murilo Nogueira de Lima Pastana
• Support Opportunities: Scholarships in Brazil - Master